Emulsion concentrates



EMULSION CON CENTRATES Ernest T. Fronczak and Paul R. Chapman, CrystalLake, and Elmer W. Brennan, West Dundee, l]l., assignors to Tfhe hrlureOil Company, Chicago, 111., a corporation 0 o This invention relates tothe preparation of stable emulsion-soluble soaps and to preparation ofstable emulsion concentrates from such soaps.

fEmulsion-soluble soaps consist of a fatty acid soap in a water-oil-soapemulsion. They differ from conventional soluble oils in that theycontain no coupling agents. One of the principal uses ofemulsion-soluble soaps is for form-parting compositions for concrete.These soaps are applied in relatively dilute water emulsions to thefaces of the forms before the concrete is poured and prevent the driedconcrete from sticking to the faceof theform, thereby assuring a smoothsurface on the concrete structure.

It is common practice to prepare emulsion-soluble soaps in anemulsion-concentrate form by adding oil and diluting with water. Suchconcentrates are then shipped to'the' desired location where "they arediluted to the desired dilution for use. f1

Difiiculty has been experienced in preparing'satisfactory emulsionconcentrates because of instability and breakdown of the concentrate,apparently caused by entrainment of air in the mass during thesoap-forming stage.

We have discovered that emulsion concentrates of unusual stability canbe prepared if the acidity of the mass during the soap-forming stage ismaintained at not less than about 0.1% by weight oleic acid equivalent..We

have further found that the stability of emulsion concen- I trate isenhanced if all the oil content of the concentrate is added to the soapprior to dilution with water to the desired concentration. It is furtherimportant in preparing the concentrate that the acidity of the finalconcentrate be regulated to about 0.45 to 0.65% by weight oleic acidequivalent:

7 It is "an object-of our invention to provide a method for preparingemulsion-soluble soaps capable of forming stable emulsions. -It is afurther object of our invention to provide a method for preparing stableoil emulsions from emulsion-forming soaps. Other objects of theinventionwill be revealed from the following description.

In accordance with our invention, a mineral oil to be emulsified ismixed with the required amount of fatty acids so that upon reaction withan alkali a soap is formed having an acidity of not less than 0.01% byweight oleic acid equivalent, and preferably between 0.01 and 0.1%. Theoil maybe a'mineral lubricating oil fraction, preferably havinga'viscosity within the range of 145 to 165 SUS at 100 'F., or the oilcan be an acidic extract resulting from the solvent extraction ofmineral lubricating oil fractions with solvents, such as phenol,furfural and nitrobenzene, to improve the viscosity index of the mineraloil. An example of a suitable extract is a phenol extract having thefollowing characteristics:

Acid number, approximately 4.1 to 4.6, usually 4.13 APl'gravity, 16 to17 rnsnsss to 380 F.

2 Fire, 420 to 435' F. Viscosity/ F., to SUS Viscosity/210 F., 39 to 41SUS V.I.,, -20 to -27 Among the fatty acids which are useful inpreparing the soap are the usual soap-forming fatty acids containing 16to 24 carbon atoms per molecule, including but not limit ed to oleic,palmitic, star'ic' and fish acids.

The oil and fatty acid are thoroughly'mixed at ambient temperature, thatis, existing room or atmospheric temperature. After the components arethoroughly mixed, there is added thereto an alkaline reagent in anamount suflicient to react withthe fatty acids to form the soap. Thealkaline reagent may be a basic alkali or alkaline earth metal compound,such as calcium hydroxide, sodium or potassium hydroxide and carbonates.We prefer, however, to use either caustic soda or caustic potash.-

The amount of alkaline reagent added to the mixture in the soap-formingstage is critical. Sufiicient must be added in order to react with thefatty acids and form a gel-like soap structure, but the quantity ofalkaline reagent must' be regulated so that the mixture remains at alltimes on the acid side, and at the completion of the soap-forming stagethe acidity of the mixture should not be less than 0.01% by weight oleicacid equivalent. The upper limit of acidity of the soap mixture is fixedonly by the acidity of the final emulsion concentrate, which willhereafter be'discussed. We prefer to regulate the amount of alkalineagent so'that the final soap composi tion has an acidity of between 0.01and 1% by weight oleic acid equivalent.

The soap-forming stage is carried out me temperature of approximately 70to 100- F.--L0wer temperatures may be used but they increase the time ofthe soap-forming stage. Higher temperatures should be avoided since thesoap becomes dehydrated and deleteriously, affects the gel structure ofthe soap.

If the acidity is carefully regulated, as pointed out, the resultingsoap concentrate will be in a paste or gel form without any airocclusion. The soap concentrate is cooled to ambient temperature and theremainder of the mineral oil is added while adjusting the acidity byaddition, if'necessar y, of free acid so that the acidity'of the finalemulsion concentrate is between about 0.45 and0.65%'by"weight.oleic"acid equivalent. in the event that a lubricatingoil is used, it will be necessary to add free oleic acid or other fattyacid to bring the-acidity of the mixture up to the desired level. Wheresolvent extract is-used, the acidity of the mixturecan be regu'-' latedby adding the proper amount of extract.

After the oil or extract has been added to the soap- In preparingthe'initial soap concentrate, we prefer to" mix with the soap-formingingredients sufiicient ofthe oil so that the resulting soap concentratewill contain about 12-20% by weight of soap. Ordinarily, this willrequire about 40-60% by volume of the total oil usedin preparingtheemulsion concentrate. The final emulsion concentrate may containabout 610% by weight of soa'p'b'utlany desired concentration which isfound economical can be used. As previously pointed out, it is essentialthat the reaction mixture be maintained slightly acidic during and atthe end of the soap-forming stage, and preferably that sufiicient acidbe incorporated in the soap-forming mixture to achieve a free acidity ofabout 0.01 to 0.1% by weight,

This range has been found to be particularly suitable when using anacidic oil such as solvent extract as the cutback oil in making thefinished emulsion concentrate. Because of the relatively high acidity ofsolvent extract, if the soap concentrate has an acidity between 0.01 and0.1% weight oleic acid equivalent, the final concentrate can be adjustedto the desired acidity of 0.45 to 0.65% oleic acid equivalent by theaddition'of the proper amount of the extract oil. On the other hand, ifneutral oil is used as the cutback oil, it may be desirable to preparethe soap concentrate with an acidity as high as 0.7% by weightcalculated as oleic acid so that when the soap is cut back with oil andwater added to the desired concentration the resulting concentrate willhave an acidity equivalent to 0.45 to 0.65% by weight of oleic acid. Itwill be apparent, therefore, that the upper limit of acidity of the soapcon centrate is not critical except insofar as it should be regulated inaccordance with the acidity of the cut back oil to be used so that whenthe desired amount of cut back oil is added the finished concentratewill have an acidity of between 0.45 and 0.65% oleic acid equivalent. 7

Not only is it important to carefully control the acidity in thesoap-forming stage and in the final emulsion concentrate, but we havefound that the order in which the cut-back oil and water are added tothe soap concentrate in order to make the finished emulsion concentrateaffects the stability of the resulting emulsion concentrate. If thecut-back oil is all added to the soap concentrate prior to the additionof the water, highly stable concentrates result which do not cream uponfurther dilution with water. On the other hand, if the dilution water isadded prior to the addition of the cut-back oil, or if the cut-back oiland water are alternately added until the desired concern tration isachieved, the concentrates have a tendency to cream and separate tovarying degrees upon dilution with water.

The following examples are illustrative. of the invention and of theresults that can be achieved by adhering to and departing from theinvention.

Example I A soap concentrate having a free alkalinity of 0.05%

by weight, calculated as potassiam hydroxide, was prepared from thefollowing starting materials:

The mixture was stirred for 4 hours at a temperature of 80 F. but didnot form a gel pastestructure. It remained liquid and entrained a verylarge amount of air, almost doubling in volume as a result of expansionby air. The soap was not processed further.

Example II A neutral soap concentrate prepared in the same manner asdisclosed for Example I was prepared from the following ingredients:

Component: Wt. percent Phenol extract (4 Neut. No.) from 85 SUS at 100F. neutral 42.0 Oleic acid 13.12 Water 42.15 Potassium hydroxide (100%assay) 2.73

The resulting soap concentrate was a very soft paste and some airentrainment was noted. An emulsion concentrate was formed from this soapby cutting back with additional phenol extract and diluting with waterso that the resulting concentrate had an, acidity of 0.4% by weight ofoleic acid equivalent. This concentrate had. only borderline stability.The final composition of the concentrate in terms of ingredients used inits preparation was:

Component: Wt. percent Phenol extract (4 Neut. No.) from SUS at F.neutral 49.03

Oleic acid 7.66

Water 41.72

Potassium hydroxide (100% assay) 1.59

Example III A soap concentrate having an acidity of 0.05% by weightoleic acid equivalent was prepared in the manner disclosed in Example Ifrom the following ingredients:

Component: Wt. percent Phenol extract (4 Neut. No.) from 85 SUS at 100F. neutral 41.85

Oleic acid 12.9

Water 42.02

Potassium hydroxide (85% assay) 3.23

The soap concentrate formed a substantially air-free gel with theconsistency of heavy paste within 5 minutes, in contrast to Example I,where even extensive agitation did not form the gel-paste structure. Itwas diluted with a small amount of water to reduce its firmness, andafter all the cut-back oil was mixed with the soap, the requisite amountof dilution water to give the finished concentrated emulsion was addedand mixed. The proportions of the ingredients in the finished emulsionwere:

Component: Wt. percent Phenol extract (4 Neut. No.) from 85 SUS at 100F. neutral 48.93

Oleic acid 7.54

Water 41.65

Potassium hydroxide (85% assay) 1.88

The finished concentrated emulsion had a free acid content of about 0.5%by weight oleic acid equivalent. It formed stable emulsions when dilutedand mixed with water in ratios of 6 and 15 parts of water per part ofconcentrated emulsion.

Example IV A soap concentrate prepared in the manner set forth inExample I but having an acidity of about 0.75% by weight oleic acidequivalent was prepared from the fol: lowing constituents:

Component: Wt. percent Phenol extract (4 Neut. No.) from 85 SUS at 100F. neutral 38.3

Oleic acid 12.55

Water 46.2

Potassium hydroxide (85% assay) 2.95

The resulting soap was a paste-like gel substantially airfree. It wascut back with additional extract oil and emulsified with water to form aconcentrated emulsion having an acidity of about 0.9% by weight oleicacid equivalent. The concentrated emulsion set into a gel within aboutone hour, thereby affecting its usefulness and ease of handling. Diluteemulsions were prepared from the concentrate but were found to beunstable.

Example V A. A v

Example VI Example VII A concentrated emulsion was prepared in themanner disclosed in Example III except that all the dilution or cut-backoil was added to the soap concentrate prior to adding the dilutionwater. The resulting concentrated emulsion was milky-white and exhibitedonly trace creaming upon standing for'twenty-four hours. Upon dilutionwith further quantities of water it formed stable emulsions.

It will be seen, therefore, that by carrying out the steps in accordancewith this invention an emulsion concentrate is prepared which itself isstable and which forms highly stable emulsions upon dilution withfurther quantitles of water.

We claim as our invention:

1. The method of preparing a stable emulsion-concentrate capable offorming stable emulsions upon dilution with about 615 parts of water perpart of concentrate comprising mixing an acidic extract obtained by thesolvent extraction of a mineral lubricating oil fraction with a solventselected from the group consisting of phenol, furfural, andnitrobenzene, with a soap-forming fatty acid in an amount sufiicient toform a gel upon neutralization with aqueous alkali-metal hydroxidesolution, neutralizing the extract-acid mixture with sufiicient aqueousalkali-metal hydroxide solution of suflicient con- This concentrateexhibited an undesirable centration to form a gel with a free acidity ofnot less than about 0.01 percent by weight oleic acid equivalent, addingadditional acidic extract and water to produce an emulsion-concentratecontaining not more than about 5 10 percent by weight of fatty acid soapand not more than about 49 percent by weight of extract, and having anacidity of 0.45 to 0.65 percent by weight oleic acid equivalent.

2. A method according to claim -1 in which the quan- 10 tity of extractto which the fatty acids are added is about 40 to 60 percent of thetotal acidic extract used to form the emulsion concentrate.

'3. A method in accordance with claim 2 in which the neutralization stepis carried out at a temperature not higher than about 100 F.

:4. The method in accordance with claim 3 in which the extract is anacidic extract from the phenol extraction of neutral oil.

5. The method in accordance with claim 3 in which the soap-forming acidis oleic acid.

6. The method in accordance with claim 3 in which the gel is cut backwith the desired amount of extract before adding water to form theemulsion concentrate.

References Cited in the file of this patent OTHER REFERENCESSchwartz-Perry: Surface Active Agents, pub. 1949 by Intersciencepublishers, N.Y. (p. 343). Hart: A Study of Water-Miscible Mineral-OilPreparations, Ind. and Eng. Chem., vol. 21, January 1929 (pp. -90).

1. THE METHOD OF PREPARING A STABLE EMULSION-CONCENTRATE CAPABLE OFFORMING STABLE EMULSIONS UPON DILUTION WITH ABOUT 6-15 PARTS OF WATERPER PART OF CONCENTRATE COMPRISING MIXING AN ACIDIC EXTRACT OBTAINED BYTHE SOLVENT EXTRACTION OF A MINERAL LUBRICATING OIL FRACTION WITH ASOLVENT SELECTED FROM THE GROUP CONSISTING OF PHENOL, FURFURAL, ANDNITROBENZENE, WITH AN SOAP-FORMING FATTY ACID IN AN AMOUNT SUFFICIENT TOFORM A GEL UPON NEUTRALIZATION WITH AQUEOU-S ALKALI-METAL HYDROXIDESOLUTION, NEUTRALIZING THE EXTRAC-ACID MIXTURE WITH SUFFICIENT AQUEOUSALKALI-METAL HYDROXIDE SOLUTION OF SUFFICIENT CONCENTRATION OF FORM AGEL WITH A FREE ACIDITY OF NOT LESS THAN ABOUT 0.01 PERCENT BY WEIGHTOLEIC ACID EQUIVALENT, ADDING ADDITIONAL ACIDIC EXTRACT AND WATER TOPRODUCE AN EMULSION-CONCENTRATE CONTAINING NOT MORE THAN ABOUT 10PERCENT BY WEIGHT OF FATTY ACID SOAP AND NOT MORE THAN ABOUT 49 PERCENTBY WEIGHT OF EXTRACT, AND HAVING AN ACIDITY OF 0.45 TO 0.65 PERCENT BYWEIGHT OLEIC ACID EQUIVALENT.